<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>获取值的类型</title>
</head>
<body>
    
</body>
</html>
<script>
    var a = '123';
    console.log(typeof a);
    var b = 123;
    console.log(typeof b);
    var c = true;
    console.log(typeof c);
    var d = null;
    console.log(typeof d);
    var f ;
    console.log(typeof f);
</script>